Furnace terminal



April 14, 1925.

T. A. REID FURNACE TE-RMINAL Filed Nov. '7, 1922 INVENTOR Thomas/i.Re/c/ ATfORNEY WITNESSES:

Patented Apr. 14, 1925.

THOMAS A. REID, OF WILKINSBURG, PENNSYLVANIA. ASSIGNOIL TO WESTINGHOUSEELECTRIC 8:; MANUFACTURING COMPANY, ACOBPORATION OF PENNSYLVANIA.

FURNACE TERMINAL.

Application filed November 7, 1922. Serial No. 599,513.

To all 'ZLIlOHL it may concern:

lieit known that I. THOMAS A. Him), a citizen of the United States, anda resident of lVilkinsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in Furnace'lerminals, of which the following is a specification.

My invention relates tofurnaee terminals and particularly to terminalsfor heating elements or resistors such as are employed in electricfurnaces.

()ne object of my invention is to provide a furnace terminal wherein theheat losses due to conduction of the material thereof are reduced to aminimum.

Another object of my invent-ion is to provide a furnace terminal whereinthe opening in the furnace wall through which the 20 resistor elementextends is effectively sealed for preventing the passage of cool airinto the furnace through the said opening; when the temperature of thefurnace is redu ed.

Another object of my invention is to provide a furnace terminal havingthe above cluu'acteristics that may be adjusted longitudinally withrespect to the furnace wall and may be free to expand and contract whenthe temperature of the bar is varied,

Another object of my invention to provide a furnace terminal of suchmaterial and design that it may be maintained at sub-- stantially thetemperature of the resistor by current therein, regardless of theheat-insulating effect of the furnace wall through which the terminalextends.

Another object of my invention is to provide a furnace terminal whereinthe packing for closing the opening through which the terminal extendsmay readily be replaced and tightened in the event that the packingbecomes loose.

These and other objcctsthat will be made apparent throughout the furtherdescription of the invention are attained by means of the terminaldevice herein described and illustrated in the accompanying drawings,wherein- Figure 1 is a vertical sectional view of a portion of a furnacewall upon which a furnace terminal is mounted, and

Fig. 2 is an elevational view of the terminal shown in Fig. 1.

Referring to the drawing the apparatus includes a terminal bar 3 that ispreferably made of nickel and to whichv the nichrome resistor or heatingelement 4 is attached by a welding process, such, for instance, as thatdescribed in my co-pending application Serial No. 599,514, filed Nov. 7,1922. The terminal bar extends through an opening 5 in the furnace wall6 which is composed of refractory material, such as clay or fire brick,and which is reinforced on the outside by a sheet-metal plate 7 that isprovided with an opening 8 alined with the opening 5 in the furnacewall.

The escape of heated. gases from the interior of the furnace or thepassage of cool air into the furnace through the opening 5 is preventedby means of a packinggasket. 9 that is of frusto-conical shape andpreferably made of asbestos-fiber compound or other refractory material.The gasket is of a pliable nature that may be distorted by compressionand forced into contact with the furnace-wall plate 7 and the tern'iirmlbar 3 by means of a frusto-conical clamping plate 11 that is attached tothe plate 7 by means of screws 12 that extend into threaded holes 13provided in the reinforcing plate 7. hen the bolts are tightened. theclamping plate 11 compresses the packing gasket. 9 which so intimatelyengages the bar and plate that heated gases are prevented from escaping.The outer end of the terminal bar 3 is connected to the supply conductor14 by means of a terminal strap 15 that is secured to the furnace wallby an insulator 16. One of the ends of the strap is provided with aclamping plate 17 of Ushape that surrounds the terminal bar and secure-1y clamps it to the terminal plate 15 when the clamping screws 18 aretightened. It will be seen from this construction that the terminal bar3 may be removed from the furnace wall without disturbing the terminalplate. The resistor elements may, therefore, be. removed from thefurnace. for inspection or repair simply by releasing the terminal bar 3from the terminal strap 15 and loosening clamp 11 to permit bar 3 toslide through the bushing 9. The other end of the termmal strap isprovided with a terminal clip 19 to which the conductor 14. isconnected.

by the heat-insulating furnace wall, the bar is preferably made ofnickel which is noncorrosive and offers less resistance than the metalof the resistor element. The bar is so designed that itsctn'rent-carrying capacity bears such relation to the heat insulation ofthe wall through which it extends that it is maintained at substantiallythe same tem perature as the resistor.

By reason of this construction, all the heat of the resistor isconserved within the furnace for the reason that none conducted throughthe terminal bar which is operating at substantially uniformtemperature, regardless of radiating conditions surrounding it. Thisresults in a considerable economy of heat within the furnace. If theterminal bar were of such material and design as to'be unheated by thecurrent therein, it would conduct heat from the conductor with aconsequent loss of heat in the furnace.

It has been determined that an unheated terminal bar conducts as muchheat from the interior of the furnace as several square feet of properlydesigned furnace wall. It is, therefore, apparent that a terminal baroperating at substantially the same temperature as the resistor resultsin conservation of heat within the furnace.

While I have described and illustrated but one embodiment of myinvention, it will be apparent to those skilled in the art that changes,modifications, substitutions, additions and omissions may be made in theapparatus illustrated Without departing from the spirit and scope of theinvention, as setforth in the appended claims.

I claim as my invention: v 1. A furnace terminal comprising a terminalbar adapted to extend through an 0 opening in a furnace wall, arefractory gasket surrounding the bar and a gasket clamp for pressingthe gasket into contact with the wall surrounding the said opening andthe terminal bar.

2. A furnace terminal comprising a terminal bar adapted to extendthrough an opening in a furnace wall, a refractory pliable gasket offrusto-conical shape surrounding the bar and a gasket clampcorresponding in shape to that of the gasket for pressing the gasketinto contact with the wall surrounding the said opening and the terminalbar.

3. A furnace terminal comprising a terminal bar adapted to extendthrough an opening in a furnace wall, a packing gasket surrounding thebar and engaging the wall of the furnace for preventing the passage ofgases through the said opening means for adjustabl-y clamping the to thefurnace wall.

4. A furnace terminal comprising a longitudinally movable terminal baradapted to extend wall, a gasket surrounding the bar and engaging thewall for preventing the passage of gas through the said opening and aconductor strap insulated from, and supported gasket by, the furnacewall and having a terminal- 1 bar clamp thereon for permittinglongitudinal adjustment of the bar with respect to the clamp when theclamp is released.

In testimony whereof, I have hereunto? subscribed my name this 25th dayof October, 1922.

THOMAS A. REID.

and a 7 through an opening in a furnace 7

